There are many conventional traffic detection systems. Conventional detectors typically utilize sensors, either in the roadway itself, or positioned at a roadside location or on traffic lights. The most common type of vehicular sensors are inductive coils, or loops, embedded in a road surface. Other existing systems utilize video cameras, radar sensors, acoustic sensors, or magnetometers, either in the road itself, or at either the side of a roadway or positioned higher above traffic to observe and detect vehicles in a desired area.
While much attention has been paid to detecting motorized vehicles such as cars, trucks and motorcycles as they move through intersections, lesser attention has been given to the safe movement of bicycles. Bicycles are an important component of the traffic environment in many places, and create unique challenges to integrate them safely into the movement of vehicles throughout roadways, especially in urban areas.
Traditionally, bicycles have been detected via a variety of methods, such as special loops, video cameras, thermal cameras, micro radar in ground systems, and even manual push buttons. Yet each of these can be inaccurate means of robust and reliable detection, which may lead to comprised safety for bicyclists as they navigate traffic thoroughfares. The need for accurate bicycle detection generally involves ensuring that bicyclists have priority due to the greater possibility of injury from, and accidents with, higher-speed and larger motorized vehicles. For example, when a bicycle arrives at an intersection, the rider wishes to have the signal actuated so that the rider can safely cross the intersection under the green light in situations where the bicycle is accorded priority. Similarly, when crossing the intersection, the rider needs adequate time to safely cross under the green signal phase. For most intersections, there is a minimum green time that is set so that if only one motorized vehicle is detected, the light will stay green for only a short amount of time. Often this time is not adequate for a bicycle to cross the intersection safely under the green phase, due to the fact that bicycles are slower than motorized vehicles and therefore may need extra time for the minimum green phase. One problem facing traffic planners and engineers is that they typically do not set the minimum green time to account for bicyclists, because it would be used every signal cycle, whether a bicycle is present or not. So there is a need in conventional systems for uniquely differentiating bicycles from motorized vehicles so that these minimum times can be applied appropriately.
Traffic planners and engineers also require data on the volume of traffic at key points in a traffic network. This data is important for comparing volumes over periods of time to help with accurate adjustment of signal timing. Current methods of traffic detection result in a data collection that results only from a count of a total number of vehicles, which may or may not include bicycles. As the need for modified signal timing to accommodate bicyclists, as described above, becomes more critical for proper traffic management, a method for separating the count of bicycles from the count of other vehicles on a thoroughfare would greatly improve the ability to accurately manage traffic environments.